Separation device for separating impurities from gases

ABSTRACT

The invention relates to a device for separating impurities from gases, such as process gases or hydrogen, comprising a filter unit ( 25 ) for separating particular and fluid media, such as water and/or oil, comprising a coalescing unit ( 29 ) for increasing the drop volume of separated fluid media and a collection unit, preferably in the form of an absorber unit ( 15 ) for binding the separated fluid media.

The invention relates to a separation device for separating impurities from gases, such as process gases or hydrogen.

When gases are used as an operating resource, as reagents or the like in technical processes, impurities in the form of particulate and/or fluid media in the process gases in question pose a risk to operational reliability up to and including system failure, may distort analysis results or may result in other malfunctions. In many cases, in addition to particulate impurities, the available gases are also contaminated by fluid media such as water and oil. Among other things, in the case of the increased use of hydrogen (FL) for actuation purposes, it is necessary to anticipate such contamination of the gases that serve as operating resources. Freedom from particulate and fluid impurities such as water and oil, is essential to the operating ability of the relevant, associated systems such as, in particular, fuel cells.

In view of these problems, the object of the invention is to provide a separation device that allows the separation of such impurities out of process gases, in particular out of hydrogen that is provided for technical purposes.

This object is achieved according to the invention by a separation device, which has the features of Claim 1 in its entirety.

Accordingly, the invention provides that the separation device has a filter device for separating out particulate and fluid media such as water and/or oil, a coalescing device to increase the size of the droplets of fluid media that have been separated off, as well as a collecting device, which is preferably designed in the form of a absorption device that binds the fluid media that have been separated off.

According to an advantageous embodiment of the invention, the separation device has at least one separating element, which defines a primary axis, and which can be accommodated in a housing in such a way that the primary axis is oriented at least approximately vertically, wherein the absorption device is disposed in a region of the separating element that allows the transfer of fluid media from the coalescing device to the absorption device through the effect of gravity. A device is thereby created that has a simple design and that allows an independent operation without additional components because the conveyance of fluid media that have been separated off to the absorption device is self-actuating, caused by the effect of gravity.

In the case of especially advantageous embodiments, the respective separating element is designed in the manner of a filter cartridge having a support tube, which has media channels, and which coaxially encompasses the primary axis, the outside of which support tube is enclosed by coalescing device and filter device. Such a separating element can be implemented in a compact unit, which can be replaced in an easy manner at the end of each respective intended operating interval.

In an especially advantageous manner, the configuration may be such that the internal space of the support tube is subdivided into an upper discharge chamber, from which the cleaned gas can be discharged after it has passed through the filter device and the coalescing device, and into a lower absorber chamber that forms the absorption device.

For such a separation process, in which the gas that is to be cleaned flows through the separating element from the outside into the inner discharge chamber, in advantageous embodiments, the support tube is enclosed from the outside to the inside by pleated filter material of the filter device and by a part of the drainage layer that forms the coalescing device, in which pre-coagulated filter media that have been separated off by the filter device sink down to the region of the absorber chamber as the droplet size steadily increases.

A preferably multi-layered filter mat, which is made out of fiberous material, for example in the form of a metal fiber nonwoven, and which causes a pre-coagulation of fluid media, is preferably provided as a filter material.

Such a filter mat that is made of such a fiberous material can also form a so-called mesh packet.

A metallic mesh or a layer of fiberous material that has been applied according to the spun-spray method may be advantageously provided as a drainage layer.

In especially advantageous embodiments, the absorption device contains a mixture of hydrophilic substances and oleophilic substances in the absorber chamber.

Such a mixture of substances may contain substances such as silica gel or zeolite beads as hydrophilic components, and substances such as diatomaceous earth or melt-blown fiberous material as oleophilic components in the filling of the absorber chamber.

In the case of especially advantageous embodiments, the configuration may be such that the support tube comprises coaxial tube members, which are connected to one another at a connecting piece that separates the discharge chamber from the absorber chamber. Such embodiments are characterized by particular compactness, because the absorber chamber in the lower section of the composite support tube is integrated into the filter cartridge.

In the case of such a design having an assembled support tube, the configuration may be advantageously such that a fluid-restraining bather is provided on the outside of the tube member associated with the discharge chamber, which barrier is formed by a hydrophobic and/or oleophobic fabric, for example. Such a barrier may also be formed of any structure having a degree of fineness that allows the passage of gas, however which prevents the passage of drops.

The invention is explained in detail below on the basis of the embodiment depicted in the drawing. Shown are:

FIG. 1 a longitudinal section of a separating element according to an embodiment of the separation device according to the invention, and

FIG. 2 a partial cross-section of the separating element along the line II-II of FIG. 1.

The separating element depicted in FIG. 1 and designated in its entirety as 1 can be accommodated in a housing, not shown here, as a component of the separation device according to the invention. For the operation of the separation device, the separating element 1 is disposed in the associated housing in such a way that the primary axis 3 formed by the separating element 1 is oriented at least approximately vertically. When using the separation device in the case of a fueling system having a hydrogen operated drive device, the housing that is to accommodate the separating element 1 is designed for a very high pressure level of 750 to 1000 bar, for example, which is conventional for such applications, and configured in such a way that the hydrogen (H₂) that is to be cleaned flows against the separating element 1 from outside during operation, as is indicated by a flow arrow 5. The clean gas exits from an discharge chamber, which is located inside the separating element 1, and which is designated as 7, and moves upward and out.

The separating element 1 is designed in the manner of a so-called filter cartridge, having a support tube that comprises two tube members 9 and 11, which are disposed coaxially aligned with the primary axis 3 and with one another, and which are connected to one another by a connecting piece 13. Both tube members 9, 11 that form the support tube have media passages in the manner conventional for support tubes, which media passages are not numbered in the drawing. The connecting piece 13 separates the hollow space enclosed by the support tube 9, 11 in the upper discharge chamber 7, which is located in the upper tube member 9, from a lower absorber chamber 15, which is enclosed by the lower tube member 11. The absorber chamber 15 is closed at the lower end of the tube member 11 by an end piece 17 in the form of a stopper. A connector 19 is provided at the upper end of the separating element 1 for the discharge of clean gases from the discharge chamber 7, which connector extends with a connecting piece 21 into the upper end of the tube member 9 and on which a seal in the form of an O-ring 23 for connecting a line (not shown) is located.

A filter device in the form of a cylindrical filter structure 25 of virtual outer circumference is located on the outside of the separating element 1. In this case, this is a water trapping material, which, as shown in FIG. 2, is pleated and preferably has a multi-layered design. A filter structure 25 in the form of a metal fiber nonwoven, which causes a pre-coagulation of fluid media, may preferably be provided as a filter material, wherein a so-called mesh packet can be formed that is closed along a longitudinal seam 27. A drainage layer 29 is connected to the inside of the filter structure 25 as a coalescing device. In this case, the present embodiment is a structure that functions as a coalescer, in which droplets of water and/or oil, which are formed at the filter structure 25 by means of pre-coagulation, are coagulated into larger drop volumes so that these media drop down by means of gravity as the droplet size steadily increases.

Instead of the pleated filter medium, a preferably multi-layered filter mat may serve as a filter structure, which may be pleated or designed as a cylindrical rolling element. The drainage layer 29 may be a metallic mesh or a layer of fiberous material, which is applied directly to the inside of the pleated filter medium 25, for example using the spun-spray method. As soon as the droplets that are formed have sunk down into the region of the lower tube member 11 of the support tube, in which the absorber chamber 15 is located, the accumulation of formed droplets reaches the absorber chamber 15 via the fluid passages of the tube member 11. A mixture of substances comprising hydrophilic substances as well as oleophilic substances is located in the absorber chamber 15 in order to bind the fluids. In so doing, a mixture of silica gel or zeolite beads may advantageously be provided as hydrophilic components, and substances such as diatomaceous earth or melt-blown fiberous material as oleophilic components.

A fluid-retaining barrier may be provided within the drainage layer 29 along the tube member 9 associated with the discharge chamber 7, for example being formed by a hydrophobic and/or oleophobic fabric. The assembly thus formed is held together at what, in the drawing, is the lower end by means of the end piece 17, and at the upper end by means of the connector 19. There are edge members 31 or, respectively, 33 located on both of these parts 17 and 19, which project axially and overlap the facing edge of the filter mat 25. As shown in FIG. 1, these wall parts 31, 33 can be pressed inward through the application of compressive force that is applied radially inward, in order to fix the end piece 17 and connector 19 to the narrowing formed on the filter mat 25. 

1. A separation device for separating impurities from gases, such as process gases or hydrogen, having a filter device (25) for separating out particulate and fluid media such as water and/or oil, having a coalescing device (29) to increase the size of the drops of fluid media that have been separated off, as well as having a collecting device, preferably in the form of an absorption device (15), for binding the fluid media that have been separated off.
 2. The separation device according to claim 1, characterized in that said device has at least one separating element (1), which defines a primary axis (3), and which can be accommodated in a housing in such a way that the primary axis (3) is oriented at least approximately vertically, and in that the absorption device (15) is disposed in a region of the separating element (1) that allows the transfer of fluid media from the coalescing device (29) to the absorption device through the effect of gravity.
 3. The separation device according to claim 1, characterized in that the respective separating element (1) is designed in the manner of a filter cartridge having a support tube (9, 11) which has media channels, and which coaxially encompasses the primary axis (3), the outside of which support tube is enclosed by coalescing device (29) and filter device (25).
 4. The separation device according to claim 1, characterized in that the internal space of the support tube (9, 11) is subdivided into an upper discharge chamber (7), from which the cleaned gas can be discharged, and into a lower absorber chamber (15) that forms the absorption device.
 5. The separation device according to claim 1, characterized in that, for a separation process, in which the gas that is to be cleaned flows through the separating element (1) from the outside into the inner discharge chamber (7), the support tube (9, 11) is enclosed from the outside to the inside by pleated filter material of the filter device (25) and by a drainage layer (29) that forms a part of the coalescing device, in which pre-coagulated fluid media that have been separated off by the filter device (25), along with an increase in the drop size, drop down to the region of the absorber chamber (15).
 6. The separation device according to claim 1, characterized in that a preferably multi-layered filter structure (25), which is made out of fiberous material, for example in the form of a metal fiber fleece, and which causes a pre-coagulation of fluid media, is provided as a filter material.
 7. The separation device according to claim 1, characterized in that a filter structure (25) that forms a mesh packet is provided.
 8. The separation device according to claim 1, characterized in that the drainage layer (29) has a metallic mesh or a layer of fiberous material that is applied, for example according to the spun-spray method.
 9. The separation device according to claim 1, characterized in that the absorption device contains a mixture of hydrophilic substances and of oleophilic substances in the absorber chamber (15).
 10. The separation device according to claim 1, characterized in that substances such as silica gel or zeolite beads are provided as hydrophilic components, and substances such as diatomaceous earth or melt-blown fiberous material are provided as oleophilic components in the filling of the absorber chamber (15).
 11. The separation device according to claim 1, characterized in that the support tube comprises coaxial tube members (9 and 11), which are connected with one another at a connecting piece (13) that separates the discharge chamber (7) from the absorber chamber (15).
 12. The separation device according to claim 1, characterized in that a fluid-restraining barrier is provided on the outside of the tube member (9) associated with the discharge chamber (7), which barrier is formed by a hydrophobic and/or oleophobic fabric, for example. 